Application of Mass Spectrometry to Forensic Chemistry

Abstract

This paper reviews applications of mass spectrometry (MS) to forensic chemistry. Forensic chemistries have to cover the wide range of substances, and a court requests more sensitive and more reliable proof without limit. Thus MS is one of the most dependable technology for forensic chemistry. One of the most important field of forensic chemistry is analysis of drugs and toxicological substances. Especially, analysis of no-information samples so called general unknown screening (GUS) or systematic toxicological analysis (STA) is a challenging task for forensic chemists. The first topic is GUS of biological samples such as whole blood, plasma, urine, and stomach contents using MS. Gas-chromatography (GC)-MS occupied a position of “golden standard” of GUS for a long time. There is no doubt that LC-MS is currently competing with GC-MS to forensic chemistry. Though, developments of GUS procedure by LC-MS have just reported recently. Developments of GUS procedure by LC-MS are discussed about following points of view: interface types (electrospray ionization, ESI and atmospheric pressure chemical ionization, APCI); mass spectrometer (single quadrupole-MS, triplequadrupole-MS, tandem-MS, ion trap-MS, and time-of-flight-MS); mass spectral libraries; and chromatographic systems. Of course sample preparation or extraction is also essential for development of GUS, it lies outside of the scope of this review. Other forensic toxicological applications are discussed about following topics: GC-negative ion chemical ionization (NICI)-MS of benzodiazepines; LC-MS of gamma-hydroxybutyric acid (GHB); LC-inductively coupled plasma (ICP)-MS of phosphorus-containing amino acid type herbicides; LC-MS of quaternary ammonium herbicides; enanthioselective analysis of methamphetamine and related compounds by capillary-electrophoresis (CE)-MS; and single-dose detection of hypnotic sedatives. The other main field of forensic chemistry, analysis of industrial product, is also discussed as follows: ICP-MS of glass fragments, metal fragments of bullet, and dyes; LC-ICP-MS and ion chromatography-ICP-MS of arsenic compounds; pyrolysis-GC-MS of rubber and plastics; and explosive analysis by supercritical fluid chromatography-MS, GC-MS, and LC-MS. As mentioned above, application of MS to many scientific fields and development of analytical science helped forensic chemistry. Applications of MS for forensic chemistry, particularly GUS by LC-MS, might made contributions to other field such as environmental, pharmaceutical, and industrial chemistry.